2. The spark that started World War I was the assassination of Austria's Archduke Franz Ferdinand and his wife Sophie. The assassination occurred on June 28, 1914 while Ferdinand was visiting the city of Sarajevo in the Austro-Hungarian province of Bosnia-Herzegovina. Although Archduke Franz Ferdinand, the nephew of Austria's emperor and heir-apparent to the throne, was not very well liked by most, his assassination by a Serb nationalist was viewed as a great excuse to attack Austria-Hungary's troublesome neighbor, Serbia

3. Germany didn't want to fight both Russia in the east and France in the west, so they enacted their long-standing Schlieffen Plan. The Schlieffen Plan was created by Alfred Graf von Schlieffen, who was the chief of the German general staff from 1891 to 1905. Schlieffen believed that it would take about six weeks for Russia to mobilize their troops and supplies. So, if Germany placed a nominal number of soldiers in the east, the majority of Germany's soldiers and supplies could be used for a quick attack in the west.

4. The main weapon used by British soldiers in the trenches wa s the bolt- action rifle. 15 rounds could be fired in a minute and a person 1,400 metres away could be killed. Machine guns needed 4-6 men to work them and had to be on a flat surface. They had the fire- power of 100 guns

5. The German army were the first to use chlorine gas at the battle of Ypres in 1915. Chlorine gas causes a burning sensation in the throat and chest pains. Death is painful - you suffocate! The problem with chlorine gas is that the weather must be right. If the wind is in the wrong direction it could end up killing your own troops rather than the enemy Mustard gas was the most deadly weapon used. It was fired into the trenches in shells. It is colourless and takes 12 hours to take effect. Effects include: blistering skin, vomiting, sore eyes, internal and external bleeding. Death can take up to 5 weeks.

6. Planes were also used for the first time. At first they were used to deliver bombs and for spying work but became fighter aircraft armed with machine guns, bombs and some times cannons. Fights between two planes in the sky became known as 'dogfights'

7. Torpedoes were used by submarines. The Germans used torpedoes to blow up ships carrying supplies from America to Britain. The Germans torpedoed the passenger liner Lusitania on May 1st 1915 which sank with a loss of 1,195 lives. Americans were outraged and joined the war in 1917 on the side of the allies.

8. Tanks were used for the first time in the First World War at the Battle of the Somme. They were developed to cope with the conditions on the Western Front. The first tank was called 'Little Willie' and needed a crew of 3. Its maximum speed was 3mph and it could not cross trenches. The more modern tank was not developed until just before the end of the war. It could carry 10 men, had a revolving turret and could reach 4mph.